Traditionally, ophthalmic devices, such as a hydrogel lens, an intraocular lens or a punctal plug, include corrective, cosmetic or therapeutic qualities. A contact lens, for example, may provide vision correcting functionality, cosmetic enhancement, and/or therapeutic effects. Each function is provided by a physical characteristic of the contact lens. For example, a refractive quality may provide a vision corrective function, a pigment may provide a cosmetic enhancement, and an active agent may provide a therapeutic functionality. Such physical characteristics are accomplished without the lens entering into an energized state.
More recently, it has been theorized that active components, such as semiconductor devices, may be incorporated into a contact lens. However, the topology and size defined by the contact lens structure creates a novel and challenging environment for the definition of components and compositions that are capable of performing various functionalities. For example, it is critical that a contact lens including semiconductor devices be biocompatible and not cause damage to surrounding ocular tissue nor inhibit ocular fluid generation or flow. In particular, it is critical that a sufficient amount of oxygen is able to reach the cornea while the contact lens including semiconductor devices is worn, otherwise eye health may be negatively impacted. For example, an inadequate supply of oxygen to the cornea can result in edema or swelling, hypoxia, and can generally cause a great deal of discomfort which limits the period of time that the contact lens can be worn.
In general, during contact lens wear, oxygen can reach the cornea either by diffusion through the lens material or by freshly oxygenated tear fluid being generated by the eye under the lens during lens motion as the lens is worn. However, some contact lenses may include components or formulations that are made of materials that have low oxygen permeability and, therefore, most of the oxygen reaching the cornea is limited to oxygen from tear mixing.
Consequently, hydrogel lenses are usually preferred over other contact lens materials because they are more comfortable and allow for more oxygen to reach the eye. When a hydrogel contact lens is worn, some oxygen reaches the cornea directly by diffusion through the lens. The amount of oxygen delivered to the cornea through the lens is dependent on the oxygen permeability of the lens. As a hydrogel contact lens is repeatedly worn, however, its oxygen permeable pores can become clogged and the hydrogel material can degrade. Therefore, the oxygen permeability of the hydrogel lens is reduced over time.
As a result of the reduced oxygen permeability and resulting increased risk of damage to the cornea, temporary or disposable hydrogel contact lenses that are disposed following a particular usage time, such as two weeks, as used. However, active components may be relatively costly and, thus, may not be incorporated in disposable hydrogel lenses.
Therefore, there is a need for a hydrogel lens including a removable media insert, where the media insert is configured to be removed from a one hydrogel lens and be removably attached to another hydrogel lens to allow the incorporation of the active components in multiple hydrogel lenses.